Ophthalmic vascular manifestations in eosinophil-associated diseases: a comprehensive analysis of 57 patients from the CEREO and EESG networks and a literature review.

Introduction: Eosinophils have widespread procoagulant effects. In daily practice, eosinophil-related cardiovascular toxicity consists of endomyocardial damage, eosinophilic vasculitis and arterial or venous thrombosis. Here we aim to report on the clinical features and treatment outcomes of patients with unexplained ophthalmic vascular manifestations and eosinophilia. Methods: We conducted a retrospective, multicenter, observational study and a literature review of patients with eosinophilia (≥0.5 x109/L) and concomitant ophthalmic vascular manifestations independent of the underlying eosinophilic disease but with no alternative cause for ophthalmic manifestations. Results: Fifty-seven patients were included (20 from the observational study and 37 from the literature review). Ophthalmic vascular features were the initial manifestation of eosinophil-related disease in 34 (59%) patients and consisted of 29 central retinal artery occlusions, six branch retinal artery occlusions, five central retinal vein occlusions, two branch retinal vein occlusions, seven retinal vasculitides, two retinal vasospasms, 12 Purtscher's retinopathies, 13 anterior ischemic optic neuropathies and two posterior ischemic optic neuropathies. The median [IQR] absolute eosinophil count at onset of ophthalmic vascular manifestations was 3.5 [1.7-7.8] x109/L. Underlying eosinophil-related diseases included eosinophilic granulomatosis with polyangiitis (n=32), clonal hypereosinophilic syndrome (HES) (n=1), idiopathic HES (n=13), lymphocytic HES (n=2), adverse drug reactions (n=3), parasitosis (n=2), polyarteritis nodosa (n=1), IgG4-related disease (n=1), eosinophilic fasciitis (n=1) and primary sclerosing cholangitis (n=1). Other extra-ophthalmologic arterial or venous thromboses related to eosinophilia were reported in four (7%) and nine (16%) patients, respectively. Visual prognosis was poor: only eight (10%) patients achieved full recovery of ophthalmologic symptoms. After a median follow-up of 10.5 [1-18] months, one patient (3%) had a recurrence of an ophthalmic vascular manifestation, and three patients (10%) had a recurrence of other vascular symptoms (deep vein thrombosis in two and pulmonary embolism in one patient). At the time of recurrence, absolute eosinophil counts were above 0.5 x109/L in all cases (n=4). Discussion: This study broadens the spectrum of vascular manifestations associated with hypereosinophilia by adding ophthalmic vascular manifestations. In patients with ophthalmological vascular manifestations and hypereosinophilia, aggressive treatment of the underlying pathology (and normalization of blood count) should be implemented.

Clinical spectrum and outcome of Takayasu's arteritis in children.

OBJECTIVES: We aimed to compare clinical spectrum and outcome between adults and children with Takayasu's arteritis (TAK) in a European population. METHODS: We made a nationwide retrospective observational study between 1988 and 2019. All adult patients met the ACR diagnostic criteria for TAK and all children met the EULAR/PRINTO/PRES criteria for paediatric TAK. RESULTS: We identified 46 children and 389 adults with TAK. The male to female ratio was 34/46 (0.74) in the paediatric group compared to 241/274 (0.88) in the adult group (P<0.05). Children presented with significantly more systemic symptoms; i.e., fever (P<0.05), fatigue (P<0.001), weight loss (P<0.001), abdominal pain (P<0.05), and myalgia (P<0.05) while adults had more upper limb claudication (P<0.01). Topography of the lesions differed significantly between the two groups: adults had more damage at the cerebral vasculature (P<0.01), upper and lower limbs (P<0.001) while children had more kidney lesions (P<0.05). Children TAK had more frequent (P<0.01) and higher (P<0.001) biological inflammation than adults. Children received higher dose-weight of corticosteroids (P=0.001) and less biotherapy (P<0.010) at diagnosis. Relapses (P<0.05) and death (8.6% vs 4.9%) were more frequent in children TAK than in adults. CONCLUSION: Paediatric TAK seems more severe than adult TAK. Therefore, paediatrics patients may require closer monitoring and systemic use of biological treatment.

Relapsing Polychondritis With Palmoplantar Pustulosis.

Palmoplantar pustulosis (PPP) is a very rare cutaneous manifestation observed during relapsing polychondritis (RP),1,2 not found in other conditions associated with saddle nose (eg, granulomatosis with polyangiitis, sarcoidosis, VEXAS [vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic] syndrome, congenital syphilis, leprosy, septal abscess).

A 24-Year-Old Woman With Cough, Arthralgia, and Skin Ulcerations.

CASE PRESENTATION: A 24-year-old Senegalese woman without remarkable history except anemia and iron deficiency related to excessive menstrual bleeding and sickle cell trait was admitted to our internal medicine department with 4-month fever, weight loss (-13 kg), dyspnea for limited efforts, intermittent productive cough, and bilateral metacarpophalangeal (MCP) and interphalangeal arthralgia. She was born and lived in France. She traveled previously to Senegal in 2015. She had no history of tobacco, alcohol, or drug use nor proximity with animals. She was taking no medication.

Neutrophilic dermatosis and hidradenitis suppurativa in patients with Behçet's disease: A neutrophilic disease in the spectrum of autoinflammatory syndromes.

BACKGROUND: Association of neutrophilic dermatosis (ND), hidradenitis suppurativa (HS) and Behçet's disease (BD) and shared efficacy of TNFα axis blockade suggests common physiopathology. OBJECTIVES: To investigate the clinical features and therapeutic response of ND and HS associated with BD. METHODS: We identified 20 patients with ND or HS associated with BD among 1462 patients with BD. RESULTS: We analysed 20 (1.4%) patients diagnosed with ND or HS associated with BD: 13 HS, 6 pyoderma gangrenosum (PG), and 1 SAPHO. Our 6 PG cases over 1462 BD patients accounts for 400/100 000 prevalence. Thirteen had bipolar aphthosis, 6 vascular, 5 neurologic, and 4 ocular involvements. All PG occurred on limbs and had typical histology with constant dermal neutrophilic infiltrate. All HS had the classical axillary-mammary phenotype. Sixty-nine percent (69%) of HS were Hurley 1 stage. Treatment consisted mainly in colchicine (n = 20), glucocorticoids (n = 12), and anti-TNFα (n = 9). Interesting results with complete or partial responses were obtained with anti-TNFα (9 cases), ustekinumab (3 cases) and tocilizumab (1 case) to treat refractory ND or HS associated with BD. CONCLUSION: PG seems overrepresented in patients with BD. Biotherapies such as anti-TNFα, ustekinumab and tocilizumab appear to be promising to treat refractory ND or HS associated with BD.

Occurrence of focal myositis during Behçet's disease: The identification of a specific vasculitis-associated focal myopathy.

AIMS: This study aimed to report the association of focal myositis (FM) and Behçet's disease (BD) and to analyse the main characteristics of such an association. METHODS: This is a retrospective multicentre study of patients with BD and FM (BD + FM+ group) and those without FM (BD - FM+ group). Clinical, laboratory, radiological, pathological, treatment and outcome data were analysed. RESULTS: The BD + FM+ group included 10 patients; the median [interquartile range] age at BD diagnosis was 25 [16-35] years, and at FM diagnosis, it was 30 [26-42] years. The diagnosis of BD preceded FM in the majority of cases (n = 8/10). FM occurrence was associated with BD flare-ups in three cases. The creatine kinase levels remained normal or slightly increased. Histological analyses identified relatively preserved muscle tissue, associated with vasculitis (n = 5/6). All patients required treatment; most patients relapsed (n = 9/10). The BD - FM+ group included 35 patients. A comparison of the groups identified a trend towards a younger median age at diagnosis of FM among those with BD (p = 0.063) and more frequent focal muscle swelling in the BD + FM+ group (p = 0.029). The pathological analysis identified significantly less frequent muscle alterations in the BD + FM+ group (muscle fibre size heterogeneity, p = 0.021; necrosis, p = 0.007; and fibrosis, p = 0.027). BD + FM+ patients had a higher frequency of relapse (p = 0.003) and systematic treatment (p = 0.042). CONCLUSIONS: FM occurring during BD appears to be part of the systemic vasculitis process and presents as a vasculitis-associated focal myopathy with a specific clinico-histological pattern. Patients with this association require long-term follow-up and adapted management. This case series also highlights the need for research on BD diagnostic criteria in cases of FM.

Pachymeningitis associated with IgG4-related disease and ANCA positivity: Case report and review of the literature.

OBJECTIVE: Hypertrophic pachymeningitis is a rare clinical disorder involving localized or diffuse thickening of the dura mater. Considering pachymeningitis is both in the clinical spectrum of IgG4-RD and ANCA vasculitis (specifically granulomatosis with polyangiitis), an overlap syndrome is discussed. METHODS: We report a case of hypertrophic pachymeningitis revealed by headache and cranial nerve dysfunction, and coexistence of biopsy-proven IgG4-RD pachymeningitis and MPO-ANCA positivity. Furthermore, all cases previously reported in the literature of pachymeningitis with IgG4-RD and presence of ANCA were analyzed. RESULTS: Thirteen patients with pachymeningitis, IgG4-RD and ANCA were analyzed. Patients with HP-related IgG4 and ANCA are mainly male (8, 62%). Median age at diagnosis was 64 years. Main clinical manifestations at diagnosis were localized to the head and neck with headaches (10, 77%), cranial nerve dysfunction (7, 54%), hearing impairment (6, 46%) and vertigo (4, 31%). Except 1 patient with diffuse aortitis, no other systemic manifestation was observed at diagnosis and during follow-up. Serum IgG4 was often elevated (11, 85%) and ANCA was mainly with myeloperoxidase specificity (11, 85%). Seven patients had cerebrospinal fluid analyse with lymphocytic pleocytosis in 5 cases (71%), elevated proteins in 4 cases (57%), positive oligoclonal bands in 3 cases (42%) and decreased glucose in one case (14%). On the MRI, the thickening of the dura mater concerned most often the posterior fossa, in 7 cases (54%). Among 10 cases with histological findings, all showed increased IgG4-positivity of plasma cells, 50% lymphocytic infiltrate but none presented the three major histological criteria of IgG4-related disease. Three (30%) showed histological signs of vasculitis with vascular wall damage and/or giant cells. Among the 12 patients treated with steroid therapy, a clinical improvement was noted in 11 cases (92%). Relapse occurred during tapering in 4 patients (33%). An immunosuppressive drug was added in 2nd line for 7 cases (54%), with a clinical improvement in all. CONCLUSION: Pachymeningitis with IgG4 and ANCA seems a localized disease to the head and neck. Leptomeningeal biopsy commonly found IgG4 criteria and no vasculitis. All patients responded well to steroid therapy and immunosuppressive drugs, especially rituximab, with clinical and radiological improvement but relapse and/or sequelae are not uncommon.

18-Fluorodeoxyglucose positron emission tomography/computed tomography for large vessel vasculitis in clinical practice.

Diagnosis, prognostic assessment, and monitoring disease activity in patients with large vessel vasculitis (LVV) can be challenging. Early recognition of LVV and treatment adaptation is essential because vascular complications (aneurysm, dilatations, ischemic complications) or treatment related side effects can occur frequently in these patients. 18-fluorodeoxyglucose positron emission tomography/computed tomography (2-[18F]FDG-PET/CT) is increasingly used to diagnose, follow, and evaluate treatment response in LVV. In this review, we aimed to summarize the current evidence on the value of 2-[18F]FDG-PET/CT for diagnosis, follow, and treatment monitoring in LVV.

COVID-19 presentation and outcomes in patients with inflammatory rheumatic and musculoskeletal diseases receiving IL6-receptor antagonists prior to SARS-CoV-2 infection.

Objective: COVID-19 outcome may be less favourable in patients with inflammatory rheumatic and musculoskeletal diseases (RMD) receiving immunosuppressive therapy. We aimed to investigate whether RMD patients on anti-IL6 therapy prior to SARS-CoV-2 infection have less severe disease and better outcomes of COVID-19. Methods: We conducted a retrospective national, multicentre cohort study using data from the French RMD COVID-19 cohort. We compared the severity and outcome of highly suspected or confirmed COVID-19 infection in RMD patients previously treated with tocilizumab or sarilumab (anti-IL6 group) with patients who did not receive anti-IL6 therapy (no anti-IL6 group). Results: Data were collected for 1883 patients with mean age of 55.2 years [SD 16.7] and 1256 (66.7%) female. Two hundred ten (11.1%) developed severe COVID-19 and 115 (6.4%) died. After adjusting for potential confounding factors, severe COVID-19 was less frequent in the anti-IL6 group compared with the no anti-IL6 group (aOR for moderate vs. mild severity, 0.23 [95% CI, 0.10 to 0.54], p ≤ 0.01 and aOR for severe vs. mild, 0.29 [95% CI, 0.10 to 0.81], p ≤ 0.01). No significant differences were found for the evolution of COVID-19 between the anti-IL6 group and the no anti-IL6 group (aOR for recovery with sequelae vs recovery without sequelae, 0.78 [95% CI, 0.41 to 1.48] and aOR for death vs recovery without sequelae, 0.29 [95% CI, 0.07 to 1.30]). Conclusion: RMD patients receiving anti-IL6 therapy prior to SARS-CoV-2 infection have less severe forms of COVID-19. No difference was observed in COVID-19 evolution, i.e., sequelae or death, between the groups.

COVID-19 outcomes in giant cell arteritis and polymyalgia rheumatica versus rheumatoid arthritis: A national, multicenter, cohort study.

OBJECTIVES: To determine whether giant cell arteritis and polymyalgia rheumatica (GCA/PMR) represent independent risk factors for worse outcomes in COVID-19. METHODS: Observational, national, French, multicenter cohort (NCT04353609) comprising patients aged ≥18 years with confirmed diagnoses of either GCA, PMR or rheumatoid arthritis (RA) having presented COVID-19; those under rituximab were excluded. Primary endpoint was COVID-19 severity in GCA/PMR patients as compared to RA. We also aimed to describe the evolution of GCA/PMR patients following COVID-19. Multinomial logistic regression models were performed, with and without adjustment on pre-specified confounding factors (i.e., age, sex, body mass index, arterial hypertension, diabetes and cardiovascular disease). Unadjusted and adjusted multinomial odds-ratio (OR/aOR) and their 95% confidence intervals (CIs) were calculated as effect size using RA as reference group. RESULTS: Between April 15, 2020, and August 20, 2021, 674 patients [45 (6.6%) GCA, 47 (7.0%) PMR, 582 (86.4%) RA; 62.8 years, 73.2% female] were included. Compared to RA patients, those with GCA/PMR were older and more frequently presented hypertension, diabetes and cardiovascular disease. Severe COVID-19 and death occurred in 24 (26.1%) and 16 (17.8%) patients with GCA/PMR, respectively. Unadjusted analyses revealed higher odds of severe COVID-19 [OR = 3.32 (95% CI 1.89-5.83; p < 0.001)] and death [OR = 3.20 (95%CI 1.67-6.13; p < 0.001)] for GCA/PMR compared to RA. After model adjustment, these odds were attenuated. CONCLUSION: Patients with GCA/PMR were more likely to have severe COVID-19 and higher mortality compared to those with RA. This worse prognosis is mostly due to well known risk factors for the general population rather than vasculitis per se.

Cerebrovascular Ischemic Events in Patients With Takayasu Arteritis.

BACKGROUND: Takayasu arteritis (TA) is a large vessel vasculitis that may complicate with cerebrovascular ischemic events. The objective was to describe clinical and vascular features of TA patients with cerebrovascular ischemic events and to identify risk factors for these events. METHODS: We analyzed the prevalence and type of stroke/transient ischemic attack (TIA), factors associated with cerebrovascular ischemic events, and stroke-free survival in a large cohort fulfilling the American College of Rheumatology or Ishikawa criteria of TA. RESULTS: Among 320 patients with TA (median age at diagnosis, 36 [25-47] years; 261 [86%] women), 63 (20%) had a stroke (n=41; 65%) or TIA (n=22; 35%). Ischemic event localized in the carotid territory for 55 (87%) patients and the vertebral artery territory in 8 (13%) patients. Multiple stenosis were observed in 33 (52%) patients with a median number of stenosis of 2 (minimum, 0 to maximum, 11), and aneurysms were observed in 10 (16%) patients. A history of stroke or TIA before TA diagnosis (hazard ratio [HR], 4.50 [2.45-8.17]; P<0.0001), smoking (HR, 1.75 [1.01-3.02]; P=0.05), myocardial infarction history (HR, 0.21 [0.05-0.89]; P=0.039), thoracic aorta involvement (HR, 2.05 [1.30-3.75]; P=0.023), time from first symptoms to diagnosis >1 year (HR, 2.22 [1.30-3.80]; P=0.005), and aspirin treatment (HR, 1.82 [1.04-3.19]; P=0.035) were associated with cerebrovascular ischemic event. In multivariate analysis, time from first symptoms to TA diagnosis >1 year (HR, 2.16 [1.27-3.70]; P=0.007) was independently associated with cerebrovascular ischemic events in patients with TA. The HR for cerebrovascular ischemic event in patients who already experienced a stroke/TIA was 5.11 (2.91-8.99; P<0.0001), compared with those who had not. CONCLUSIONS: Carotid stroke/TIA is frequent in TA. We identified factors associated with cerebrovascular ischemic events.

HCV-related lymphoproliferative disorders in the direct-acting antiviral era: From mixed cryoglobulinaemia to B-cell lymphoma.

HCV has been shown to induce many B-cell lymphoproliferative disorders. B lymphocytes specialise in producing immunoglobulins and, during chronic HCV infection, they can cause manifestations ranging from polyclonal hypergammaglobulinaemia without clinical repercussions, through mixed cryoglobulinaemic vasculitis to B-cell non-Hodgkin lymphoma. This spectrum is supported by substantial epidemiological, pathophysiological and therapeutic data. Many, although not all, of the pathogenic pathways leading from one extreme to another have been decrypted. Chronic viral antigen stimulation of B lymphocytes has a central role until the final steps before overt malignancy. This has direct implications for treatment strategies, which always include the use of direct-acting antivirals sometimes alongside immunosuppressants. The role of direct-acting antivirals has been well established in patients with cryoglobulinaemia vasculitis. However, their positive impact on B-cell non-Hodgkin lymphoma needs to be confirmed in larger studies with longer follow-up.

Mast cells drive pathologic vascular lesions in Takayasu arteritis.

BACKGROUND: Takayasu arteritis (TAK) is a large vessel vasculitis resulting in artery wall remodeling with segmental stenosis and/or aneurysm formation. Mast cells (MCs) are instrumental in bridging cell injury and inflammatory response. OBJECTIVES: This study sought to investigate the contribution of MCs on vessel permeability, angiogenesis, and fibrosis in patients with TAK. METHODS: MC activation and their tissue expression were assessed in sera and in aorta from patients with TAK and from healthy donors (HDs). In vivo permeability was assessed using a modified Miles assay. Subconfluent cultured human umbilic vein endothelial cells and fibroblasts were used in vitro to investigate the effects of MC mediators on angiogenesis and fibrogenesis. RESULTS: This study found increased levels of MC activation markers (histamine and indoleamine 2,3-dioxygenase) in sera of patients with TAK compared with in sera of HDs. Marked expression of MCs was shown in aortic lesions of patients with TAK compared with in those of noninflammatory aorta controls. Using Miles assay, this study showed that sera of patients with TAK significantly increased vascular permeability in vivo as compared with that of HDs. Vessel permeability was abrogated in MC-deficient mice. MCs stimulated by sera of patients with TAK supported neoangiogenesis (increased human umbilic vein endothelial cell proliferation and branches) and fibrosis by inducing increased production of fibronectin, type 1 collagen, and α-smooth muscle actin by fibroblasts as compared to MCs stimulated by sera of HD. CONCLUSIONS: MCs are a key regulator of vascular lesions in patients with TAK and may represent a new therapeutic target in large vessel vasculitis.

Spectrum and Outcome of Noninfectious Aortitis.

OBJECTIVE: To assess the spectrum and long-term outcome of patients with noninfectious aortitis. METHODS: We performed a retrospective multicenter study of 353 patients (median age at diagnosis was 62 [IQR 46-71] yrs and 242 [68.6%] patients were women) with noninfectious aortitis. Factors associated with vascular complications were assessed in multivariate analysis. RESULTS: We included 136 patients with giant cell arteritis (GCA), 96 with Takayasu arteritis (TA), 73 with clinically isolated aortitis (CIA), and 48 with aortitis secondary to inflammatory diseases (including Behçet disease, relapsing polychondritis, IgG4-related disease, Cogan syndrome, ankylosing spondylitis). After a median follow-up of 52 months, vascular complications were observed in 32.3%, revascularizations in 30% of patients, and death in 7.6%. The 5-year cumulative incidence of vascular complications was 58% (95% CI 41-71), 20% (95% CI 13-29), and 19% (95% CI 11-28) in CIA, GCA, and TA, respectively. In multivariate analysis, male sex (HR 2.10, 95% CI 1.45-3.05, P < 0.0001) and CIA (HR 1.76, 95% CI 1.11-2.81, P = 0.02) were independently associated with vascular complications. CONCLUSION: Noninfectious aortitis accounts for significant morbidity and mortality. CIA seems to carry the highest rate of vascular complications.

Pregnancy issues in Takayasu arteritis.

Takayasu arteritis (TAK) is a chronic inflammatory vasculitis of unknown origin affecting large vessels, predominantly the aorta and its main branches. TAK usually affects young women and the management of pregnancy during this vasculitis may be a challenging situation. After a review of the literature, we analysed the data of 505 pregnancies in 373 TAK patients. We discuss main results to clarify if the pregnancy outcome is affected by TAK, especially during disease clinical onset or disease activity. We also discuss the potential impact of pregnancy on TAK prognosis. Disease activity of TAK appears independently associated with a poor pregnancy outcome. More than 5% of pregnant women with TAK develop a life-threatening maternal cardiovascular complication. A good control of TAK disease activity and arterial hypertension before conception and during pregnancy is critical to improve both maternal and foetal outcomes. Pregnancies in the setting of TAK should be considered high-risk, requiring a close collaboration between specialists involved in the care of TAK and obstetricians.

Treatment of chronic hepatitis C-associated cryoglobulinemia vasculitis at the era of direct-acting antivirals.

Hepatitis C virus (HCV) infection is responsible for both hepatic and extrahepatic manifestations. Before the era of direct-acting antivirals (DAA), cryoglobulinemia was related to HCV infection in 70-90% of cases. Observed in 30% to 40% of patients with hepatitis C, mixed cryoglobulinemia is mainly asymptomatic. Conversely, symptomatic cryoglobulinemia vasculitis (CV) can occur in 5-10% of patients with HCV-associated cryoglobulinemia. CV is a small-vessel systemic vasculitis, and organ damage results from circulation and precipitation of cryoglobulins and complement activation. A wide range of clinical symptoms can be observed during CV, and manifestations are potentially life-threatening. The most frequent manifestations occurring in CV are cutaneous, with recurrent purpura, articular with joint pains, neurologic with peripheric neuropathy, and renal with membranoproliferative glomerulonephritis. DAA have drastically changed chronic HCV therapy. DAA induce sustained virological response (SVR) rates greater than 95%, and also improve extrahepatic manifestations such as CV. We review recent studies investigating the clinical and immune effects of DAA therapy on HCV-CV.

Immunomodulatory role of Interleukin-33 in large vessel vasculitis.

The mechanisms regulating inflammation in large vessels vasculitis (LVV) are poorly understood. Interleukin 33 (IL-33) has been shown to license innate and adaptive immunity by enhancing Th2 cytokines production. We aimed to examine the role of IL-33 in the immunomodulation of T cell activation in LVV. T cell homeostasis and cytokines production were determined in peripheral blood from 52 patients with giant cell arteritis (GCA) and 50 healthy donors (HD), using Luminex assay, flow cytometry, quantitative RT-PCR and by immunofluorescence analysis in inflammatory aorta lesions. We found increased level of IL-33 and its receptor ST2/IL-1R4 in the serum of patient with LVV. Endothelial cells were the main source of IL-33, whereas Th2 cells, Tregs and mast cells (MC) express ST2 in LVV vessels. IL-33 had a direct immunomodulatory impact by increasing Th2 and Tregs. IL-33 and MC further enhanced Th2 and regulatory responses by inducing a 6.1 fold increased proportion of Tregs (p = 0.008). Stimulation of MC by IL-33 increased indoleamine 2 3-dioxygenase (IDO) activity and IL-2 secretion. IL-33 mRNA expression was significantly correlated with the expression of IL-10 and TGF-ß within aorta inflammatory lesions. To conclude, our findings suggest that IL-33 may exert a critical immunoregulatory role in promoting Tregs and Th2 cells in LVV.

Targeting JAK/STAT pathway in Takayasu's arteritis.

OBJECTIVE: Takayasu's arteritis (TAK) is a large vessel vasculitis with important infiltration of proinflammatory T cells in the aorta and its main branches, but its aetiology is still unknown. Our work aims to explore the involvement of Janus Kinase/Signal Transducers and Activators of Transcription (JAK/STAT) signalling pathway in proinflammatory T cells differentiation and disease activity of TAK. METHODS: We analysed transcriptome and interferons gene signatures of fluorescence-activated cell sorting (FACS-sorted) CD4+ and CD8+ T cells from healthy donors (HD) and in 25 TAK (median age of 37.6 years including 21 active TAK with National Institutes of Health (NIH) score >1). Then we tested, in vitro and in vivo, the effects of JAK inhibitors (JAKinibs) in TAK. RESULTS: Transcriptome analysis showed 248 and 432 significantly dysregulated genes for CD4+ and CD8+ samples between HD and TAK, respectively. Among dysregulated genes, we highlighted a great enrichment for pathways linked to type I and type II interferons, JAK/STAT and cytokines/chemokines-related signalling in TAK. We confirmed by Real Time Reverse Transcription Polymerase Chain Reaction (RT-qPCR) the upregulation of type I interferons gene signature in TAK as compared with HD. JAKinibs induced both in vitro and in vivo a significant reduction of CD25 expression by CD4+ and CD8+ T cells, a significant decrease of type 1 helper T cells (Th1) and Th17 cells and an increase of Tregs cells in TAK. JAKinibs also decreased C reactive protein level, NIH score and corticosteroid dose in TAK patients. CONCLUSIONS: JAK/STAT signalling pathway is critical in the pathogenesis of TAK and JAKinibs may be a promising therapy.